Development of suitable working Protocol for in vitro Tape Stripping : A Case Study with biocompatible Aceclofenac-loaded topical Nanoemulsions

Considering the numerous organizational and legislative issues associated with in vivo studies, the present study aimed to develop in vitro tape stripping protocol that could serve as a prospective technique for skin penetration studies. The research was mainly focused on the suitability of transepidermal water loss (TEWL) measurements, as a barrier integrity test for porcine ear skin subjected to freezing/thawing procedure, as well as on the selection of the most suitable device for pressing adhesive tapes onto the porcine ear surface during skin stripping procedure. Obtained results suggest that TEWL measurements were able to detect the damage of the stratum corneum (SC) caused by physical impairment (using adhesive tapes) and tissue degradation/dehydration (prolonged storage at –20ºC/ambient conditions). Penetration profiles of aceclofenac from nanoemulsions based on sucrose esters or polysorbate 80 as coemulsifiers, obtained in vitro (using a roller as pressure device), were in a good agreement with data obtained in vivo on humans, supporting the use of developed in vitro tape-stripping protocol in skin formulation development and optimization.